Circulating Ang II (A), MMP2 (B) and MMP9 (C) are elevated in the blood samples from AAD complicated with lung injury patients. Ang II, MMP9 and MMP2 were assayed by the systems for each marker in the human peripheral blood samples from healthy control volunteers (n=12); patients with nonruptured, chronic aortic aneurysm (n=12); AAD patients without ALI (n=37) or AAD complicated with ALI patients (n=21). **P<0.01 versus control. Ang II, angiotensin II; AAD, acute aortic dissection; MMP9 indicates matrix metalloproteinase 9.